I want to test a cleanup function in the return of useEffect but I’m unable to simulate unmounting a component.

Code I want to test:

  useEffect(() => {
        () => clearError(); //I can't cover this line
    }, []);

What I have tried
1.

        let cleanupFunc;

        jest.spyOn(React, 'useEffect')
            .mockImplementationOnce(jest.fn())
            .mockImplementationOnce(jest.fn())
            // third useEffect - clear errors
            .mockImplementationOnce((func) => {
                cleanupFunc = func();
            });

        render(<Component {...props} />);
      
        cleanupFunc();

Error: TypeError: cleanupFunc is not a function

2.

     const { unmount } = render(<Component {...props} />)
        unmount()

        expect(props.clearError).toHaveBeenCalledTimes(1)

This one is not causing the cleanup function to be executed